JP2007205729A - Sensor and inspection device - Google Patents

Sensor and inspection device Download PDF

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JP2007205729A
JP2007205729A JP2006021588A JP2006021588A JP2007205729A JP 2007205729 A JP2007205729 A JP 2007205729A JP 2006021588 A JP2006021588 A JP 2006021588A JP 2006021588 A JP2006021588 A JP 2006021588A JP 2007205729 A JP2007205729 A JP 2007205729A
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magnetic detection
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magnetic
detection
conductor pattern
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JP5037017B2 (en
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Goro Takeuchi
悟朗 竹内
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Hioki EE Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor capable of improving inspection accuracy. <P>SOLUTION: This device is equipped with a pair of magnetic detection elements 41a, 41b arranged in the mutually separated state at a prescribed distance, for detecting magnetism from a magnetism generator and outputting detection signals Sda, Sdb; and a differential amplifier 32 for outputting a differential signal Sm between the detection signals Sda, Sdb outputted respectively from each magnetic detection element 41a, 41b. In this case, the magnetic detection elements 41a, 41b having the same magnetic detection characteristic can be used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、磁気検出素子を備えたセンサ、およびそのセンサを備えた検査装置に関するものである。   The present invention relates to a sensor including a magnetic detection element, and an inspection apparatus including the sensor.

この種のセンサとして、特開平８−２３３８６７号公報に開示されたブリッジ検出回路が知られている。このブリッジ検出回路は、１つの半導体磁気抵抗素子を有するブリッジ、増幅回路および同期加算回路等を備えて、導線に電流が流れることに起因して生じる磁気（磁束）を検出可能に構成されている。このため、このブリッジ検出回路を用いることで、例えば、回路基板における導体パターンの断線や短絡等の検査を非接触で行うことが可能となる。
特開平８−２３３８６７号公報（第３頁、第１図） As this type of sensor, a bridge detection circuit disclosed in JP-A-8-233867 is known. This bridge detection circuit includes a bridge having one semiconductor magnetoresistive element, an amplifier circuit, a synchronous adder circuit, and the like, and is configured to be able to detect magnetism (magnetic flux) generated due to current flowing through a conducting wire. . For this reason, by using this bridge detection circuit, it becomes possible to inspect, for example, disconnection or short circuit of the conductor pattern in the circuit board in a non-contact manner.
JP-A-8-233867 (page 3, FIG. 1)

ところが、従来のブリッジ検出回路を用いて、例えば、多層回路基板に実装された集積回路の裏面側に配設された端子と多層回路基板の導体パターンとの接続状態の良否を検査する際には、不都合が生じる。具体的に、図８〜図１０に示すように、導体パターン２０２，２０３を有する多層回路基板２０１に実装された集積回路２１１の端子２１２と導体パターン２０２との接続状態の良否を上記のブリッジ検出回路を用いて検査する例について説明する。   However, using a conventional bridge detection circuit, for example, when inspecting the quality of the connection state between the terminals arranged on the back side of the integrated circuit mounted on the multilayer circuit board and the conductor pattern of the multilayer circuit board, Inconvenience arises. Specifically, as shown in FIGS. 8 to 10, the above bridge detection is performed to determine whether or not the connection state between the terminal 212 of the integrated circuit 211 mounted on the multilayer circuit board 201 having the conductor patterns 202 and 203 and the conductor pattern 202 is good. An example of inspection using a circuit will be described.

この検査において、例えば、図８に示すように、集積回路２１１（例えば、集積回路２１１ａ）の端子２１２と導体パターン２０２との接触状態が良好のときには、導体パターン２０２のうちの導体パターン２０２ａ，２０２ｂに印加された検査用信号が導体パターン２０２ｂから端子２１２に向かって流れるため、端子２１２および導体パターン２０２ｂで発生した磁気がブリッジ検出回路によって検出される結果、両者の接触状態が良好であるとの正しい判定をすることができる。また、図９に示すように、集積回路２１１（例えば、集積回路２１１ｂ）の端子２１２と導体パターン２０２ｂとの接続状態が不良のときには、導体パターン２０２ｂから端子２１２に向けて検査用信号が流れないため、ブリッジ検出回路によって磁気が検出されない結果、両者の接触状態が不良であるとの正しい判定をすることができる。   In this inspection, for example, as shown in FIG. 8, when the contact state between the terminal 212 of the integrated circuit 211 (for example, the integrated circuit 211a) and the conductor pattern 202 is good, the conductor patterns 202a and 202b of the conductor pattern 202 are used. Since the inspection signal applied to the terminal flows from the conductor pattern 202b toward the terminal 212, the magnetism generated at the terminal 212 and the conductor pattern 202b is detected by the bridge detection circuit. As a result, the contact state between the two is good. The correct judgment can be made. Further, as shown in FIG. 9, when the connection state between the terminal 212 of the integrated circuit 211 (for example, the integrated circuit 211b) and the conductor pattern 202b is poor, the inspection signal does not flow from the conductor pattern 202b to the terminal 212. Therefore, as a result of the magnetism not being detected by the bridge detection circuit, it is possible to correctly determine that the contact state between the two is defective.

一方、図１０に示すように、集積回路２１１（例えば、集積回路２１１ｃ）の端子２１２と導体パターン２０２ｂとの接続状態が不良であったとしても、導体パターン２０２ｂと導体パターン２０２ｃとが導体パターン２０２ｄで接続されていて、導体パターン２０２ａ，２０２ｂに印加された検査用信号が他の集積回路２１１（例えば集積回路２１１ｄ）を介して導体パターン２０３に流れているときには、導体パターン２０３で発生した磁気がブリッジ検出回路によって検出される。   On the other hand, as shown in FIG. 10, even if the connection state between the terminal 212 of the integrated circuit 211 (for example, the integrated circuit 211c) and the conductor pattern 202b is poor, the conductor pattern 202b and the conductor pattern 202c are connected to the conductor pattern 202d. When the inspection signal applied to the conductor patterns 202a and 202b flows to the conductor pattern 203 via another integrated circuit 211 (for example, the integrated circuit 211d), the magnetism generated in the conductor pattern 203 is It is detected by a bridge detection circuit.

この場合、この種の半導体磁気抵抗素子は、一般的に、図５に示すように、磁気発生体までの距離が長くなるのに従って磁気を検出する検出感度比が低下する特性を有している。このため、半導体磁気抵抗素子と導体パターン２０３との距離が十分に長いときには、半導体磁気抵抗素子の検出感度比が低下する結果、導体パターン２０３で発生した磁気がブリッジ検出回路によって検出されないか、またはブリッジからは微弱な検出信号しか出力されないこととなる。しかしながら、半導体磁気抵抗素子と導体パターン２０３との距離が比較的短いときには、導体パターン２０３で発生した磁気がブリッジ検出回路によって検出される結果、端子２１２と導体パターン２０２ｂとの接続状態が不良であるにも拘わらず、両者の接触状態が良好であるかのような誤った判定がされるおそれがある。したがって、このブリッジ検出回路では、この種の検査の検査精度が低下するおそれがある。   In this case, this type of semiconductor magnetoresistive element generally has a characteristic that the detection sensitivity ratio for detecting magnetism decreases as the distance to the magnetic generator increases as shown in FIG. . For this reason, when the distance between the semiconductor magnetoresistive element and the conductor pattern 203 is sufficiently long, the detection sensitivity ratio of the semiconductor magnetoresistive element decreases, so that the magnetism generated in the conductor pattern 203 is not detected by the bridge detection circuit, or Only a weak detection signal is output from the bridge. However, when the distance between the semiconductor magnetoresistive element and the conductor pattern 203 is relatively short, the magnetism generated in the conductor pattern 203 is detected by the bridge detection circuit, resulting in a poor connection state between the terminal 212 and the conductor pattern 202b. Nevertheless, there is a risk of erroneous determination as if the contact state between the two is good. Therefore, in this bridge detection circuit, there is a possibility that the inspection accuracy of this type of inspection is lowered.

本発明は、かかる問題点に鑑みてなされたものであり、検査精度を向上し得るセンサおよび検査装置を提供することを主目的とする。   The present invention has been made in view of such problems, and a main object of the present invention is to provide a sensor and an inspection apparatus that can improve inspection accuracy.

上記目的を達成すべく請求項１記載のセンサは、所定距離だけ互いに離間した状態で配置される一対の磁気検出素子と、前記各磁気検出素子によってそれぞれ出力される検出信号の差分信号を出力する差動回路とを備えている。   In order to achieve the above object, the sensor according to claim 1 outputs a pair of magnetic detection elements arranged apart from each other by a predetermined distance, and a difference signal between detection signals output by the magnetic detection elements. And a differential circuit.

また、請求項２記載のセンサは、請求項１記載のセンサにおいて、前記各磁気検出素子は、同一の磁気検出特性を有している。   According to a second aspect of the present invention, in the sensor according to the first aspect, each of the magnetic detection elements has the same magnetic detection characteristic.

また、請求項３記載のセンサは、所定距離だけ互いに離間した状態で配置される３つの磁気検出素子と、前記各磁気検出素子のうちの中央に位置する１つの当該磁気検出素子によって出力される検出信号と他の前記磁気検出素子によって出力される検出信号との差分信号を出力する差動回路とを備えている。   The sensor according to claim 3 is output by three magnetic detection elements arranged in a state of being separated from each other by a predetermined distance, and one magnetic detection element located in the center of the magnetic detection elements. A differential circuit for outputting a differential signal between the detection signal and the detection signal output by the other magnetic detection element.

また、請求項４記載の検査装置は、請求項１から３のいずれかに記載のセンサと、当該センサによって出力される前記差分信号に基づいて磁気発生体についての電気的パラメータを検査する検査部とを備えている。   According to a fourth aspect of the present invention, there is provided an inspection apparatus that inspects an electrical parameter of a magnetic generator based on the sensor according to any one of the first to third aspects and the difference signal output by the sensor. And.

請求項１記載のセンサによれば、所定距離だけ互いに離間した状態で配置された一対の磁気検出素子と、各磁気検出素子によってそれぞれ出力される検出信号の差分信号を出力する差動回路とを備えてセンサを構成したことにより、単一の磁気検出素子、つまり従来のブリッジ検出回路と比較して、磁気発生体までの距離の増加に対する検出感度比の低下率を大きくすることができる。このため、センサに近接する磁気発生体で発生する磁気を確実に検出し、かつセンサから離れた磁気発生体からの磁気の検出を十分に抑えることができる結果、例えば多層の回路基板における内層の導体パターンで磁気が発生しているときに、回路基板における表層の導体パターンと集積回路の端子との接続状態が不良であるにも拘わらず、両者の接触状態を良好と誤って判定する事態を確実に防止することができる。したがって、このセンサによれば、この種の検査に対する検査精度を十分に向上させることができる。   According to the sensor of the first aspect, the pair of magnetic detection elements arranged in a state of being separated from each other by a predetermined distance, and the differential circuit that outputs a differential signal of the detection signals respectively output by the magnetic detection elements. By providing the sensor, the rate of decrease in the detection sensitivity ratio with respect to the increase in the distance to the magnetic generator can be increased as compared with a single magnetic detection element, that is, a conventional bridge detection circuit. For this reason, it is possible to reliably detect the magnetism generated by the magnetic generator close to the sensor and sufficiently suppress the detection of magnetism from the magnetic generator away from the sensor. When magnetism is generated in a conductor pattern, there is a situation where the contact state between the surface layer conductor pattern on the circuit board and the terminal of the integrated circuit is erroneously judged as good even though the connection state between the terminals is bad. It can be surely prevented. Therefore, according to this sensor, the inspection accuracy for this type of inspection can be sufficiently improved.

また、請求項２記載のセンサによれば、同一の（つまり互いに同じ）磁気検出特性を有する磁気検出素子を用いたことにより、例えば、磁気検出特性が互いに異なる磁気検出素子を用いる構成とは異なり、各磁気検出特性に応じた利得で検出信号を増幅する等の各磁気検出素子毎の調整を行うことなく、磁気検出素子同士の距離を調整するだけで、センサの磁気検出特性を任意に調整することができる。   In addition, according to the sensor of the second aspect, since the magnetic detection elements having the same (that is, the same) magnetic detection characteristics are used, for example, different from the configuration using magnetic detection elements having different magnetic detection characteristics. Without adjusting each magnetic detection element such as amplifying the detection signal with a gain corresponding to each magnetic detection characteristic, the magnetic detection characteristic of the sensor can be arbitrarily adjusted by simply adjusting the distance between the magnetic detection elements. can do.

また、請求項３記載のセンサによれば、所定距離だけ互いに離間した状態で配置された３つの磁気検出素子と、各磁気検出素子のうちの中央に位置する１つの磁気検出素子によって出力される検出信号とその磁気検出素子を除く他の磁気検出素子によって出力される検出信号との差分信号を出力する差動回路とを備えてセンサを構成したことにより、単一の磁気検出素子と比較して、センサに近接する磁気発生体で発生する磁気を確実に検出し、かつセンサから離れた磁気発生体からの磁気の検出を十分に抑えることができる結果、例えば多層の回路基板における内層の導体パターンで磁気が発生しているときに、回路基板における表層の導体パターンと集積回路の端子との接続状態が不良であるにも拘わらず、両者の接触状態を良好と誤って判定する事態を確実に防止することができる。したがって、このセンサによれば、この種の検査に対する検査精度を十分に向上させることができる。   In addition, according to the sensor of the third aspect, output is performed by three magnetic detection elements arranged in a state of being separated from each other by a predetermined distance and one magnetic detection element located in the center of the magnetic detection elements. Compared with a single magnetic detection element by configuring a sensor with a differential circuit that outputs a differential signal between the detection signal and a detection signal output by another magnetic detection element other than the magnetic detection element. As a result, it is possible to reliably detect the magnetism generated by the magnetic generator close to the sensor and sufficiently suppress the detection of magnetism from the magnetic generator away from the sensor. When the pattern is magnetized, the contact state between the surface conductor pattern on the circuit board and the terminal of the integrated circuit is poor, but the contact state between the two is good and false. Determining a situation can be reliably prevented. Therefore, according to this sensor, the inspection accuracy for this type of inspection can be sufficiently improved.

また、請求項４記載の検査装置によれば、上記のセンサと、センサによって出力される差分信号に基づいて磁気発生体についての電気的パラメータを検査する検査部とを備えたことにより、上記のセンサが有する効果と同様の効果を実現することができる。   Further, according to the inspection apparatus of the fourth aspect, the above-described sensor and the inspection unit that inspects the electrical parameter of the magnetic generator based on the difference signal output by the sensor are provided. The same effect as that of the sensor can be realized.

以下、本発明に係るセンサおよび検査装置の最良の形態について、添付図面を参照して説明する。   Hereinafter, the best mode of a sensor and an inspection apparatus according to the present invention will be described with reference to the accompanying drawings.

最初に、基板検査装置１の構成について、図面を参照して説明する。   First, the configuration of the substrate inspection apparatus 1 will be described with reference to the drawings.

図１に示す基板検査装置１は、本発明に係る検査装置の一例であって、例えば図２に示す電子回路基板１００の良否を検査可能に構成されている。この場合、電子回路基板１００は、図２に示すように、回路基板１０１、および回路基板１０１に実装された集積回路１１１を備えている。回路基板１０１は、一例として、２層構造の基板であって、同図に示すように、表層（同図における上側の層）に導体パターン１０２が形成され、内層に導体パターン１０３が形成されている。集積回路１１１は、一例として、裏面（同図における下面）に複数の端子１１２が配列されたＢＧＡ（Ball Grid Array ）タイプの集積回路であって、回路基板１０１の導体パターン１０２に端子１１２が接続されている。   A substrate inspection apparatus 1 shown in FIG. 1 is an example of an inspection apparatus according to the present invention, and is configured to be able to inspect the quality of the electronic circuit board 100 shown in FIG. In this case, the electronic circuit board 100 includes a circuit board 101 and an integrated circuit 111 mounted on the circuit board 101, as shown in FIG. As an example, the circuit board 101 is a board having a two-layer structure. As shown in the figure, the conductor pattern 102 is formed on the surface layer (upper layer in the figure), and the conductor pattern 103 is formed on the inner layer. Yes. The integrated circuit 111 is, for example, a BGA (Ball Grid Array) type integrated circuit in which a plurality of terminals 112 are arranged on the back surface (the bottom surface in the figure), and the terminals 112 are connected to the conductor pattern 102 of the circuit board 101. Has been.

一方、基板検査装置１は、図１に示すように、検査用信号出力部２、センサ３、移動機構４、制御部５および操作部６を備えて構成されている。検査用信号出力部２は、制御部５の制御に従って検査用信号Ｓｔを出力する。また、検査用信号出力部２には、図２に示すように、電子回路基板１００の導体パターン１０２に検査用信号Ｓｔを印加するためのプローブ２３ａ，２３ｂが接続されている。センサ３は、図１に示すように、磁気検出部３１および差動アンプ３２を備えている。磁気検出部３１は、一対の磁気検出素子４１ａ，４１ｂ（以下、区別しないときには「磁気検出素子４１」ともいう）、スペーサ４２およびケース４３を備えて構成されている。磁気検出素子４１ａ，４１ｂは、一例として、単位磁界（１エルステッド（Ｏｅ））当りの出力電圧（Ｖ）で規定される検出感度Ｓがそれぞれ１．６Ｖ／Ｏｅであって、かつ互いに同じ磁気検出特性（図５参照）を有するＭＲ（Magneto Resistance）素子で構成されて、磁気を検出して検出信号Ｓｄａ，Ｓｄｂ（以下区別しないときには「検出信号Ｓｄ」ともいう）をそれぞれ出力する。なお、磁気検出素子４１の検出感度Ｓは上記の値に限定されず、極性を異ならせたときの合計値が０となる任意の値に規定することができる。また、磁気検出素子４１ａ，４１ｂは、同図に示すように、スペーサ４２を介して所定の距離だけ離間した状態で互いに対向するようにして筒状のケース４３の内部に収容（配設）されている。この場合、検査に際しては、同図に示すように、検出対象体としての磁気を発生する磁気発生体（導体パターン１０２や端子１１２などの導体：以下、これらを「検出対象体」ともいう）に磁気検出素子４１ａ側を向けるように、つまりこの例では磁気検出素子４１ａ側を下向きにした状態でセンサ３（磁気検出部３１）を検出対象体に近接させる。   On the other hand, the substrate inspection apparatus 1 includes an inspection signal output unit 2, a sensor 3, a moving mechanism 4, a control unit 5, and an operation unit 6, as shown in FIG. The inspection signal output unit 2 outputs an inspection signal St according to the control of the control unit 5. Further, as shown in FIG. 2, probes 23 a and 23 b for applying the inspection signal St to the conductor pattern 102 of the electronic circuit board 100 are connected to the inspection signal output unit 2. As shown in FIG. 1, the sensor 3 includes a magnetic detection unit 31 and a differential amplifier 32. The magnetic detection unit 31 includes a pair of magnetic detection elements 41 a and 41 b (hereinafter also referred to as “magnetic detection element 41” when not distinguished), a spacer 42, and a case 43. As an example, the magnetic detection elements 41a and 41b have the same magnetic detection in which the detection sensitivities S defined by the output voltage (V) per unit magnetic field (1 Oersted (Oe)) are 1.6 V / Oe, respectively. It is composed of an MR (Magneto Resistance) element having characteristics (see FIG. 5), and detects magnetism and outputs detection signals Sda and Sdb (hereinafter also referred to as “detection signal Sd” when not distinguished). In addition, the detection sensitivity S of the magnetic detection element 41 is not limited to the above value, and can be defined as an arbitrary value in which the total value becomes 0 when the polarities are changed. Further, as shown in the figure, the magnetic detection elements 41a and 41b are accommodated (arranged) in a cylindrical case 43 so as to face each other with a predetermined distance therebetween via a spacer 42. ing. In this case, in the inspection, as shown in the figure, a magnetic generator that generates magnetism as a detection target (conductors such as the conductor pattern 102 and the terminal 112: hereinafter, these are also referred to as “detection target”). In this example, the sensor 3 (magnetic detection unit 31) is brought close to the detection target so that the magnetic detection element 41a is directed, that is, with the magnetic detection element 41a facing downward in this example.

差動アンプ３２は、本発明における差動回路に相当し、磁気検出素子４１ａ，４１ｂからそれぞれ出力される検出信号Ｓｄａ，Ｓｄｂを入力して、両検出信号Ｓｄａ，Ｓｄｂの差分信号Ｓｍを出力する。この場合、差動アンプ３２は、一例として、両磁気検出素子４１ａ，４１ｂのうちの使用時において検出対象体側に位置する磁気検出素子４１（この例では磁気検出素子４１ａ）によって出力される検出信号Ｓｄａから、その磁気検出素子４１を除く他の磁気検出素子４１（この例では磁気検出素子４１ｂ）によって出力される検出信号Ｓｄｂを差し引いた差分信号Ｓｍを出力する。   The differential amplifier 32 corresponds to the differential circuit in the present invention, receives the detection signals Sda and Sdb output from the magnetic detection elements 41a and 41b, and outputs a differential signal Sm between the detection signals Sda and Sdb. . In this case, as an example, the differential amplifier 32 detects the detection signal output by the magnetic detection element 41 (in this example, the magnetic detection element 41a) located on the detection target body side when using either of the magnetic detection elements 41a and 41b. A difference signal Sm obtained by subtracting the detection signal Sdb output from the other magnetic detection elements 41 (in this example, the magnetic detection element 41b) excluding the magnetic detection element 41 is output from Sda.

ここで、センサ３に用いられている磁気検出素子４１（つまり、従来のブリッジ検出回路）単独での磁気検出特性と、センサ３の磁気検出特性とを図５に示す。この場合、両者の磁気検出特性を比較すると、単一の磁気検出素子４１では、磁気発生体までの距離が長くなるのに従って低下する検出感度比の低下率が比較的小さいのに対して、センサ３では、この検出感度比の低下率が大きくなっている。このため、このセンサ３では、センサ３に近接する磁気発生体（検出対象体）で発生する磁気を確実に検出し、かつセンサ３から離れた磁気発生体からの磁気の検出を十分に抑えることが可能となっている。   Here, the magnetic detection characteristics of the magnetic detection element 41 (that is, the conventional bridge detection circuit) used in the sensor 3 alone and the magnetic detection characteristics of the sensor 3 are shown in FIG. In this case, when comparing the magnetic detection characteristics of the two, the single magnetic detection element 41 has a relatively small reduction rate of the detection sensitivity ratio that decreases as the distance to the magnetic generator increases. 3, the rate of decrease in the detection sensitivity ratio is large. For this reason, in this sensor 3, the magnetism which generate | occur | produces in the magnetic generation body (detection target body) close | similar to the sensor 3 is detected reliably, and the detection of the magnetism from the magnetic generation body away from the sensor 3 is fully suppressed. Is possible.

一方、検出対象体と検出対象体以外の磁気発生体とが存在するときに、検出対象体および磁気発生体に流れる電流値をそれぞれＩ１，Ｉ２、誘磁率をμとすると、検出対象体までの距離がｒ１で磁気発生体までの距離がｒ２の位置（検出位置）における磁束密度Ｂ０（磁気の強度）は、下記の（１）式で表される。
Ｂ０＝μ・Ｉ１／（２・π・ｒ１）＋μ・Ｉ２／（２・π・ｒ２）・・（１）式
したがって、センサ３の磁気検出素子４１ａをこの検出位置に位置させたときにおける、磁気検出素子４１ａによって検出される磁束密度と、磁気検出素子４１ｂによって検出される磁束密度との差分に相当する磁束密度Ｂ、つまりセンサ３によって検出される磁束密度Ｂは、磁気検出素子４１ａと磁気検出素子４１ｂとの間の距離をｄとすると、下記の（２）式で表される。
Ｂ＝μ・Ｉ１／（２・π・ｒ１）＋μ・Ｉ２／（２・π・ｒ２）−μ・Ｉ１／（２・π・（ｒ１＋ｄ））−μ・Ｉ２／（２・π・（ｒ２＋ｄ））
＝μ・Ｉ１／（２・π・ｒ１）−μ・Ｉ１／（２・π・（ｒ１＋ｄ））＋μ・Ｉ２／（２・π・ｒ２）−μ・Ｉ２／（２・π・（ｒ２＋ｄ））・・（２）式 On the other hand, when there are a detection object and a magnetic generator other than the detection object, if the current values flowing through the detection object and the magnetic generator are I 1 and I 2 , and the inductivity is μ, the detection object The magnetic flux density B 0 (magnetic intensity) at the position (detection position) where the distance to the magnetic generator is r 1 and the distance to the magnetic generator is r 2 is expressed by the following equation (1).
B 0 = μ · I 1 / (2 · π · r 1 ) + μ · I 2 / (2 · π · r 2 ) ·· (1) Therefore, the magnetic detection element 41a of the sensor 3 is positioned at this detection position. The magnetic flux density B corresponding to the difference between the magnetic flux density detected by the magnetic detection element 41a and the magnetic flux density detected by the magnetic detection element 41b, that is, the magnetic flux density B detected by the sensor 3, is When the distance between the detection element 41a and the magnetic detection element 41b is d, it is expressed by the following equation (2).
B = μ · I 1 / (2 · π · r 1 ) + μ · I 2 / (2 · π · r 2 ) −μ · I 1 / (2 · π · (r 1 + d)) − μ · I 2 / (2 · π · (r 2 + d))
= Μ · I 1 / (2 · π · r 1 ) −μ · I 1 / (2 · π · (r 1 + d)) + μ · I 2 / (2 · π · r 2 ) −μ · I 2 / (2 · π · (r 2 + d)) ·· (2) Formula

また、上記（２）式のうちの下記の（３）式で表される成分は、磁束密度Ｂのうちの検出対象体で発生する磁束密度の成分に相当する。
μ・Ｉ１／（２・π・ｒ１）−μ・Ｉ１／（２・π・（ｒ１＋ｄ））・・（３）式
また、（３）式の左側部分は磁気検出素子４１ａによって検出される磁束密度に相当し、（３）式の右側部分は磁気検出素子４１ｂによって検出される磁束密度に相当する。この場合、通常では、検出対象体に磁気検出素子４１ａを近接させるため、距離ｒ１が距離ｄと比較して十分に短い結果、下記の（４）式が満たされる結果、（３）式の右側部分によって表される磁気検出素子４１ｂによって検出される磁束密度の影響が小さくなる。
ｒ１≪ｒ１＋ｄ・・（４）式 The component represented by the following equation (3) in the equation (2) corresponds to the component of the magnetic flux density generated in the detection target body in the magnetic flux density B.
μ · I 1 / (2 · π · r 1 ) −μ · I 1 / (2 · π · (r 1 + d)) ·· (3) Also, the left side of the equation (3) is the magnetic detection element 41a. The right part of the equation (3) corresponds to the magnetic flux density detected by the magnetic detection element 41b. In this case, in the normal, in order to close the magnetic detection element 41a in the detection object, the distance r 1 is sufficiently short results in comparison with the distance d, the result of the following formula (4) is satisfied, the equation (3) The influence of the magnetic flux density detected by the magnetic detection element 41b represented by the right portion is reduced.
r 1 «r 1 + d ·· ( 4) formula

一方、上記（２）式のうちの下記の（５）式で表される成分は、磁束密度Ｂのうちの検出対象体以外の磁気発生体で発生する磁束密度の成分に相当する。
μ・Ｉ２／（２・π・ｒ２）−μ・Ｉ２／（２・π・（ｒ２＋ｄ））・・（５）式
また、（５）式の左側部分は磁気検出素子４１ａによって検出される磁束密度に相当し、（５）式の右側部分は磁気検出素子４１ｂによって検出される磁束密度に相当する。この場合、通常では、距離ｒ２が距離ｄと比較して十分に長い結果、下記の（６）式が満たされるため、（５）式の右側部分の値と、左側部分の値とがほぼ同じ値となる結果、（５）式によって算出される値が０に近い値となる。つまり、検出対象体以外の磁気発生体で発生する磁束密度の影響が少ない状態に維持される。
ｒ２≒ｒ２＋ｄ・・（６）式
この場合、このセンサ３では、上記の（２）〜（６）式と、各磁気検出素子４１ａ，４１ｂの磁気検出特性や、電子回路基板１００における集積回路１１１の上面から導体パターン１０２，１０３までの距離等とに基づき、磁気検出素子４１ａと磁気検出素子４１ｂとの間の距離ｄが例えば３ｍｍ程度に規定されている。 On the other hand, the component represented by the following equation (5) in the equation (2) corresponds to the component of the magnetic flux density generated in the magnetic generator other than the detection target in the magnetic flux density B.
μ · I 2 / (2 · π · r 2 ) −μ · I 2 / (2 · π · (r 2 + d)) (5) Also, the left side of the equation (5) is the magnetic detection element 41a. The right part of the equation (5) corresponds to the magnetic flux density detected by the magnetic detection element 41b. In this case, normally, the distance r 2 is sufficiently longer than the distance d, so that the following expression (6) is satisfied. Therefore, the value on the right side and the value on the left side of the expression (5) are almost equal. As a result of the same value, the value calculated by equation (5) is close to zero. That is, the influence of the magnetic flux density generated by the magnetic generator other than the detection target is kept small.
r 2 ≈r 2 + d (6) In this case, in this sensor 3, the above-described equations (2) to (6), the magnetic detection characteristics of the magnetic detection elements 41a and 41b, and the electronic circuit board 100 Based on the distance from the upper surface of the integrated circuit 111 to the conductor patterns 102 and 103, etc., the distance d between the magnetic detection element 41a and the magnetic detection element 41b is defined to be about 3 mm, for example.

移動機構４は、制御部５の制御に従ってプローブ２３ａ，２３ｂを移動させることにより、電子回路基板１００の導体パターン１０２にプローブ２３ａ，２３ｂの先端部を接触させる。また、移動機構４は、制御部５の制御に従い、電子回路基板１００の上方においてセンサ３を移動させる。制御部５は、本発明における検査部に相当し、センサ３の差動アンプ３２から出力された差分信号Ｓｍに基づいて検出対象体に流れる電流値Ｉｍを算出する。また、制御部５は、予め規定された閾値Ｉｒと算出した電流値Ｉｍとを比較することにより、導体パターン１０２と端子１１２との接続状態の良否の判定（本発明における、導体についての電気的パラメータの検査）を行う。この場合、閾値Ｉｒは、端子１１２と導体パターン１０２とが良好な状態で接続されているときに検出対象体に流れる電流値、つまり、この状態において検出対象体で発生する磁気が磁気検出部３１によって検出された際に出力される差分信号Ｓｍに対応する電流値よりもやや低い値に規定されている。さらに、制御部５は、移動機構４によるプローブ２３ａ，２３ｂおよびセンサ３の移動を制御する。操作部６は、測定の開始操作等の各種の操作が可能に構成されている。   The moving mechanism 4 moves the probes 23 a and 23 b under the control of the control unit 5, thereby bringing the tips of the probes 23 a and 23 b into contact with the conductor pattern 102 of the electronic circuit board 100. The moving mechanism 4 moves the sensor 3 above the electronic circuit board 100 according to the control of the control unit 5. The control unit 5 corresponds to the inspection unit in the present invention, and calculates the current value Im flowing through the detection target based on the differential signal Sm output from the differential amplifier 32 of the sensor 3. Further, the control unit 5 compares the predetermined threshold value Ir with the calculated current value Im, thereby determining whether or not the connection state between the conductor pattern 102 and the terminal 112 is good (in the present invention, the electrical Perform parameter inspection). In this case, the threshold value Ir is the value of the current that flows through the detection object when the terminal 112 and the conductor pattern 102 are connected in a good state, that is, the magnetism generated in the detection object in this state is the magnetic detection unit 31. Is defined as a value slightly lower than the current value corresponding to the differential signal Sm output when detected by. Further, the control unit 5 controls the movement of the probes 23 a and 23 b and the sensor 3 by the moving mechanism 4. The operation unit 6 is configured to be capable of various operations such as a measurement start operation.

次に、基板検査装置１を用いて電子回路基板１００における各集積回路１１１の各端子１１２と導体パターン１０２との接続状態の良否を検査する回路基板検査方法について、図面を参照して説明する。   Next, a circuit board inspection method for inspecting the quality of the connection state between each terminal 112 of each integrated circuit 111 and the conductor pattern 102 in the electronic circuit board 100 using the board inspection apparatus 1 will be described with reference to the drawings.

まず、操作部６を用いて、検査の開始操作を行う。次いで、制御部５が、操作部６の操作に従って移動機構４を制御してプローブ２３ａ，２３ｂを移動させることにより、図２に示すように、回路基板１０１の導体パターン１０２（例えば、同図に示す導体パターン１０２ａ，１０２ｂ）にプローブ２３ａ，２３ｂの先端部をそれぞれ接触させる。また、制御部５は、検査用信号出力部２を作動させて、検査用信号Ｓｔを出力させる。この際に、検査用信号出力部２から出力された検査用信号Ｓｔがプローブ２３ａ，２３ｂを介して導体パターン１０２ａ，１０２ｂ間に印加される。   First, an inspection start operation is performed using the operation unit 6. Next, the control unit 5 controls the moving mechanism 4 in accordance with the operation of the operation unit 6 to move the probes 23a and 23b, so that the conductor pattern 102 (for example, FIG. The tip portions of the probes 23a and 23b are brought into contact with the conductor patterns 102a and 102b) shown. Further, the control unit 5 operates the inspection signal output unit 2 to output the inspection signal St. At this time, the inspection signal St output from the inspection signal output unit 2 is applied between the conductor patterns 102a and 102b via the probes 23a and 23b.

続いて、制御部５は、移動機構４を制御して、図２に示すように、電子回路基板１００における各集積回路１１１のうちの１つ（例えば、同図に示す集積回路１１１ａ）の上面に沿ってセンサ３の磁気検出部３１を移動させて、集積回路１１１ａにおける各端子１１２のうちの１つ（例えば同図に示す端子１１２ａ）に接続された集積回路１１１ａ内の導体（例えばボンディングワイヤ）から磁気検出部３１の磁気検出素子４１ａまでの距離が例えば１．５ｍｍ上方に離間した位置で磁気検出部３１を停止させる。ここで、例えば、導体パターン１０２と端子１１２ａとの接続状態が良好なときには、プローブ２３ａ，２３ｂを介して印加された検査用信号Ｓｔが、導体パターン１０２から端子１１２ａを介して集積回路１１１ａ内を流れるため、磁気検出部３１の磁気検出素子４１ａ，４１ｂが端子１１２ａおよび端子１１２ａの周囲の導体パターン１０２で発生する磁気Ｍ１を検出して検出信号Ｓｄａ，Ｓｄｂをそれぞれ出力する。   Subsequently, the control unit 5 controls the moving mechanism 4 so that the upper surface of one of the integrated circuits 111 (for example, the integrated circuit 111a shown in FIG. 2) in the electronic circuit board 100, as shown in FIG. The magnetic detection unit 31 of the sensor 3 is moved along the conductor, and a conductor (for example, a bonding wire) in the integrated circuit 111a connected to one of the terminals 112 (for example, the terminal 112a shown in the figure) in the integrated circuit 111a. ) To the magnetic detection element 41a of the magnetic detection unit 31 is stopped at a position where the distance is, for example, 1.5 mm upward. Here, for example, when the connection state between the conductor pattern 102 and the terminal 112a is good, the inspection signal St applied through the probes 23a and 23b passes through the integrated circuit 111a from the conductor pattern 102 through the terminal 112a. Therefore, the magnetic detection elements 41a and 41b of the magnetic detection unit 31 detect the magnetism M1 generated in the conductor pattern 102 around the terminal 112a and the terminal 112a and output detection signals Sda and Sdb, respectively.

この際に、差動アンプ３２が、検出信号Ｓｄａ，Ｓｄｂを入力して、検出信号Ｓｄａから検出信号Ｓｄｂを差し引いた差分信号Ｓｍを出力する。この場合、このセンサ３では、上記したように、近接する検出対象体で発生する磁気Ｍ１を確実に検出することが可能となっている。このため、センサ３は、磁気Ｍ１に応じたレベルの差分信号Ｓｍを確実に出力する。次いで、制御部５は、センサ３（差動アンプ３２）から出力された差分信号Ｓｍに基づいて検出対象体に流れる電流値Ｉｍを算出すると共に、算出した電流値Ｉｍと閾値Ｉｒとを比較する。この場合、端子１１２ａと導体パターン１０２との接続状態が良好なため、電流値Ｉｍは閾値Ｉｒよりもやや高い値となる。したがって、制御部５は、端子１１２ａと導体パターン１０２との接続状態が良好であると判定する。続いて、制御部５は、上記の動作と同様に動作することにより、集積回路１１１ａにおける他の端子１１２についての接続状態の良否の判定を繰り返して実行する。   At this time, the differential amplifier 32 inputs the detection signals Sda and Sdb, and outputs a differential signal Sm obtained by subtracting the detection signal Sdb from the detection signal Sda. In this case, as described above, the sensor 3 can reliably detect the magnetism M1 generated in the adjacent detection target object. For this reason, the sensor 3 reliably outputs the differential signal Sm having a level corresponding to the magnetism M1. Next, the control unit 5 calculates the current value Im flowing through the detection target based on the difference signal Sm output from the sensor 3 (differential amplifier 32), and compares the calculated current value Im with the threshold value Ir. . In this case, since the connection state between the terminal 112a and the conductor pattern 102 is good, the current value Im is slightly higher than the threshold value Ir. Therefore, the control part 5 determines with the connection state of the terminal 112a and the conductor pattern 102 being favorable. Subsequently, the control unit 5 operates in the same manner as the above operation, thereby repeatedly determining whether or not the connection state of the other terminal 112 in the integrated circuit 111a is good.

次に、集積回路１１１ａの全ての端子１１２について上記の判定が完了したときには、制御部５は、移動機構４を制御してプローブ２３ａ，２３ｂを移動させることにより、図３に示すように、他の導体パターン１０２（例えば、同図に示す導体パターン１０２ｃ，１０２ｄ）にプローブ２３ａ，２３ｂの先端部をそれぞれ接触させる。続いて、制御部５は、移動機構４を制御して、同図に示すように、各集積回路１１１のうちの他の１つ（例えば、同図に示す集積回路１１１ｂ）の上面に沿ってセンサ３を移動させて、集積回路１１１ｂにおける各端子１１２のうちの１つ（例えば同図に示す端子１１２ｂ）に接続された集積回路１１１ｂ内の導体（例えばボンディングワイヤ）から磁気検出素子４１ａまでの距離が１．５ｍｍ上方に離間した位置でセンサ３を停止させる。   Next, when the above determination is completed for all the terminals 112 of the integrated circuit 111a, the control unit 5 controls the moving mechanism 4 to move the probes 23a and 23b, as shown in FIG. The tip portions of the probes 23a and 23b are brought into contact with the conductor pattern 102 (for example, the conductor patterns 102c and 102d shown in the figure). Subsequently, the control unit 5 controls the moving mechanism 4 to move along the upper surface of the other one of the integrated circuits 111 (for example, the integrated circuit 111b shown in the figure) as shown in the figure. The sensor 3 is moved so that a conductor (for example, a bonding wire) in the integrated circuit 111b connected to one of the terminals 112 (for example, the terminal 112b shown in the figure) in the integrated circuit 111b to the magnetic detection element 41a. The sensor 3 is stopped at a position where the distance is 1.5 mm apart.

ここで、図３に示すように、例えば、端子１１２ｂと導体パターン１０２との接続が不良（両者が非接続状態）のときには、検査用信号Ｓｔが集積回路１１１ａ内を流れないため、端子１１２ｂおよび端子１１２ｂの周囲の導体パターン１０２で磁気が発生していない。一方、このセンサ３では、上記したように離れた磁気発生体からの磁気の検出を十分に抑えることが可能となっている。このため、例えば、移動機構４の動力源等で磁気が発生しているとしても、その磁気の検出が抑えられる結果、この状態では、センサ３は、０または極めて低いレベルの差分信号Ｓｍを出力する。次いで、制御部５は、差分信号Ｓｍに基づいて電流値Ｉｍを算出して閾値Ｉｒとを比較する。この場合、差分信号Ｓｍのレベルが０または極めて低いため、電流値Ｉｍは閾値Ｉｒよりも低い値となる。したがって、制御部５は、端子１１２ｂと導体パターン１０２との接続状態が不良であると判定する。続いて、制御部５は、上記の動作と同様に動作することにより、集積回路１１１ｂにおける他の端子１１２についての接続状態の良否の判定を繰り返して実行する。   Here, as shown in FIG. 3, for example, when the connection between the terminal 112b and the conductor pattern 102 is poor (both are not connected), the test signal St does not flow through the integrated circuit 111a. Magnetism is not generated in the conductor pattern 102 around the terminal 112b. On the other hand, this sensor 3 can sufficiently suppress the detection of magnetism from a distant magnetic generator as described above. For this reason, for example, even if magnetism is generated in the power source of the moving mechanism 4 or the like, detection of the magnetism is suppressed. As a result, in this state, the sensor 3 outputs a differential signal Sm of 0 or an extremely low level. To do. Next, the control unit 5 calculates the current value Im based on the difference signal Sm and compares it with the threshold value Ir. In this case, since the level of the difference signal Sm is 0 or extremely low, the current value Im is lower than the threshold value Ir. Therefore, the control unit 5 determines that the connection state between the terminal 112b and the conductor pattern 102 is defective. Subsequently, the control unit 5 operates in the same manner as the above operation, thereby repeatedly determining whether or not the connection state of the other terminal 112 in the integrated circuit 111b is good.

次に、集積回路１１１ｂの全ての端子１１２について上記の判定が完了したときには、制御部５は、移動機構４を制御してプローブ２３ａ，２３ｂを移動させることにより、図４に示すように、他の導体パターン１０２（例えば、同図に示す導体パターン１０２ｅ，１０２ｆ）にプローブ２３ａ，２３ｂの先端部をそれぞれ接触させる。次いで、制御部５は、移動機構４を制御して、同図に示すように、各集積回路１１１のうちの他の１つ（例えば、同図に示す集積回路１１１ｃ）の上面に沿ってセンサ３を移動させて、集積回路１１１ｃにおける各端子１１２のうちの１つ（例えば同図に示す端子１１２ｃ）に接続された集積回路１１１ｃ内の導体（例えばボンディングワイヤ）から磁気検出素子４１ａまでの距離が１．５ｍｍ上方に離間した位置でセンサ３を停止させる。ここで、同図に示すように、例えば、端子１１２ｃと導体パターン１０２との接続が不良（両者が非接続状態）のときには、検査用信号Ｓｔが集積回路１１１ｃ内を流れないため、端子１１２ｃおよび端子１１２ｃの周囲の導体パターン１０２では、磁気が発生していない。   Next, when the above determination is completed for all the terminals 112 of the integrated circuit 111b, the control unit 5 controls the moving mechanism 4 to move the probes 23a and 23b, as shown in FIG. The tip portions of the probes 23a and 23b are brought into contact with the conductor pattern 102 (for example, the conductor patterns 102e and 102f shown in the figure). Next, the control unit 5 controls the moving mechanism 4 and, as shown in the figure, the sensor along the upper surface of the other one of the integrated circuits 111 (for example, the integrated circuit 111c shown in the figure). 3 is moved, and a distance from a conductor (for example, a bonding wire) in the integrated circuit 111c connected to one of the terminals 112 (for example, the terminal 112c shown in the figure) to the magnetic detection element 41a in the integrated circuit 111c. Stops the sensor 3 at a position spaced 1.5 mm upward. Here, as shown in the figure, for example, when the connection between the terminal 112c and the conductor pattern 102 is poor (both are not connected), the test signal St does not flow through the integrated circuit 111c. Magnetism is not generated in the conductor pattern 102 around the terminal 112c.

一方、図４に示すように、導体パターン１０２ｆと導体パターン１０２ｇとが導体パターン１０２ｈによって接続されているときには、導体パターン１０２ｅ，１０２ｆに印加された検出信号Ｓｄが、導体パターン１０２ｇに接続されている他の集積回路１１１（例えば集積回路１１１ｄ）を介して導体パターン１０３に流れるため、導体パターン１０３で磁気Ｍ２が発生する。この場合、このセンサ３では、上記したように離れた磁気発生体からの磁気の検出を十分に抑えることが可能となっている。このため、導体パターン１０３で発生している磁気Ｍ２のセンサ３による検出が抑えられる結果、この状態では、センサ３から出力される差分信号Ｓｍは十分に低いレベルに抑えられている。次いで、制御部５は、差分信号Ｓｍに基づいて電流値Ｉｍを算出して閾値Ｉｒとを比較する。この場合、単一の磁気検出素子４１、すなわち１つの半導体磁気抵抗素子を備えた従来のブリッジ検出回路では、検出対象体までの距離の増加に対する検出感度比の低下率が小さいため（図５参照）、導体パターン１０３で発生している磁気Ｍ２が検出されて、電流値Ｉｍが閾値Ｉｒ以上の値となるおそれがある。これに対して、このセンサ３では、差分信号Ｓｍのレベルが低いため、電流値Ｉｍは閾値Ｉｒよりも低い値となる。したがって、制御部５は、この状態においても、端子１１２ｃと導体パターン１０２ａとの接続状態が不良であると判定する。   On the other hand, as shown in FIG. 4, when the conductor pattern 102f and the conductor pattern 102g are connected by the conductor pattern 102h, the detection signal Sd applied to the conductor patterns 102e and 102f is connected to the conductor pattern 102g. Since the current flows through the conductor pattern 103 via another integrated circuit 111 (for example, the integrated circuit 111d), the magnetic M2 is generated in the conductor pattern 103. In this case, the sensor 3 can sufficiently suppress the detection of magnetism from the separated magnetic generator as described above. For this reason, detection by the sensor 3 of the magnetic M2 generated in the conductor pattern 103 is suppressed. As a result, in this state, the differential signal Sm output from the sensor 3 is suppressed to a sufficiently low level. Next, the control unit 5 calculates the current value Im based on the difference signal Sm and compares it with the threshold value Ir. In this case, in the conventional bridge detection circuit including a single magnetic detection element 41, that is, one semiconductor magnetoresistive element, the rate of decrease in the detection sensitivity ratio with respect to the increase in the distance to the detection target is small (see FIG. 5). ), The magnetic M2 generated in the conductor pattern 103 is detected, and the current value Im may become a value equal to or greater than the threshold value Ir. On the other hand, in this sensor 3, since the level of the differential signal Sm is low, the current value Im is lower than the threshold value Ir. Therefore, the controller 5 determines that the connection state between the terminal 112c and the conductor pattern 102a is defective even in this state.

次いで、制御部５は、上記の動作と同様に動作することにより、集積回路１１１ｃにおける他の端子１１２についての接続状態の良否の判定を繰り返して実行する。次に、全ての集積回路１１１の全ての端子１１２についての判定が完了したときには、制御部５は、その判定結果を図外の表示部に表示させて検査を終了する。   Next, the control unit 5 operates in the same manner as the above operation, thereby repeatedly determining whether or not the connection state of the other terminal 112 in the integrated circuit 111c is good. Next, when the determination for all the terminals 112 of all the integrated circuits 111 is completed, the control unit 5 displays the determination result on a display unit (not shown) and ends the inspection.

このように、このセンサ３および基板検査装置１によれば、所定の距離ｄだけ互いに離間した状態で配置された一対の磁気検出素子４１ａ，４１ｂと、各磁気検出素子４１ａ，４１ｂによってそれぞれ出力される検出信号Ｓｄの差分信号Ｓｍを出力する差動アンプ３２とを備えてセンサ３を構成したことにより、単一の磁気検出素子４１、つまり従来のブリッジ検出回路と比較して、磁気発生体までの距離の増加に対する検出感度比の低下率を大きくすることができる。このため、センサ３に近接する検出対象体としての磁気発生体で発生する磁気を確実に検出し、かつセンサ３から離れた磁気発生体からの磁気の検出を十分に抑えることができる結果、例えば多層の回路基板１０１における内層の導体パターン１０３で磁気が発生しているときに、回路基板１０１における表層の導体パターン１０２と集積回路１１１の端子１１２との接続状態が不良であるにも拘わらず、両者の接触状態を良好と誤って判定する事態を確実に防止することができる。したがって、このセンサ３および基板検査装置１によれば、この種の検査に対する検査精度を十分に向上させることができる。   As described above, according to the sensor 3 and the substrate inspection apparatus 1, the signals are output by the pair of magnetic detection elements 41a and 41b and the magnetic detection elements 41a and 41b arranged in a state of being separated from each other by a predetermined distance d. And the differential amplifier 32 for outputting the differential signal Sm of the detection signal Sd to be configured, the sensor 3 is configured so that the magnetic generator is compared with the single magnetic detection element 41, that is, the conventional bridge detection circuit. The decrease rate of the detection sensitivity ratio with respect to the increase in the distance can be increased. For this reason, as a result of reliably detecting the magnetism generated by the magnetic generator as a detection target close to the sensor 3 and sufficiently suppressing the detection of magnetism from the magnetic generator away from the sensor 3, for example When magnetism is generated in the inner conductor pattern 103 in the multilayer circuit board 101, the connection state between the surface conductor pattern 102 in the circuit board 101 and the terminal 112 of the integrated circuit 111 is poor. A situation in which the contact state between the two is erroneously determined as good can be reliably prevented. Therefore, according to this sensor 3 and the board | substrate inspection apparatus 1, the test | inspection precision with respect to this kind of test | inspection can fully be improved.

また、このセンサ３および基板検査装置１によれば、互いに同じ磁気検出特性を有する磁気検出素子４１を用いたことにより、例えば、磁気検出特性が互いに異なる磁気検出素子４１を用いる構成とは異なり、各磁気検出特性に応じた利得で検出信号Ｓｄを増幅する等の各磁気検出素子４１毎の調整を行うことなく、磁気検出素子４１同士の距離を調整するだけで、センサ３の磁気検出特性を任意に調整することができる。   Moreover, according to this sensor 3 and the board | substrate inspection apparatus 1, by using the magnetic detection element 41 which has the mutually same magnetic detection characteristic, for example, unlike the structure which uses the magnetic detection element 41 from which a magnetic detection characteristic differs, Without adjusting each magnetic detection element 41 such as amplifying the detection signal Sd with a gain corresponding to each magnetic detection characteristic, the magnetic detection characteristic of the sensor 3 can be adjusted only by adjusting the distance between the magnetic detection elements 41. It can be adjusted arbitrarily.

なお、本発明は、上記の構成に限定されない。例えば、センサ３を用いて回路基板１０１の導体パターン１０２と集積回路１１１の端子１１２との接続状態を検査可能な基板検査装置１を例に挙げて説明したが、例えば、図６に示す検査装置３００に適用することもできる。この検査装置３００では、センサ３の磁気検出特性を利用することにより、例えば、同図に示すように、近接して配設された複数本（この例では２本）の電線４０１，４０２のうちの任意の１本に電流が流れているか否かの検査が可能となってる。   In addition, this invention is not limited to said structure. For example, the substrate inspection apparatus 1 that can inspect the connection state between the conductor pattern 102 of the circuit board 101 and the terminal 112 of the integrated circuit 111 using the sensor 3 has been described as an example. For example, the inspection apparatus shown in FIG. 300 can also be applied. In this inspection apparatus 300, by using the magnetic detection characteristics of the sensor 3, for example, as shown in the figure, out of a plurality of (in this example, two) wires 401 and 402 arranged close to each other. It is possible to check whether or not a current is flowing through any one of the above.

具体的には、例えば、測定対象の２本の電線４０１，４０２のうちの電線４０１に電流が流れているか否かを検査する際には、図６に示すように、センサ３の磁気検出素子４１ａ側を電線４０１に近接させる。この際に、制御部３０５が、センサ３から出力された差分信号Ｓｍに基づく電流値Ｉｍと閾値Ｉｒとを比較して、電流値Ｉｍが閾値Ｉｒ未満のときには電線４０１に電流が流れていないと判定し、電流値Ｉｍが閾値Ｉｒ以上のときには電線４０１に電流が流れていると判定する。この場合、上記したように、センサ３が、近接する検出対象体からの磁気を確実に検出すると共に、離れた磁気発生体からの磁気の検出を十分に抑えるため、電線４０２に電流が流れているか否かに拘わらず、電線４０１で発生する磁気Ｍ１に応じたレベルの差分信号Ｓｍがセンサ３から出力される結果、電線４０１に電流が流れているか否かを正確に検査することができる。   Specifically, for example, when inspecting whether or not a current is flowing in the electric wire 401 of the two electric wires 401 and 402 to be measured, as shown in FIG. The 41a side is brought close to the electric wire 401. At this time, the control unit 305 compares the current value Im based on the difference signal Sm output from the sensor 3 with the threshold value Ir, and if the current value Im is less than the threshold value Ir, no current is flowing through the electric wire 401. When the current value Im is equal to or greater than the threshold value Ir, it is determined that a current is flowing through the electric wire 401. In this case, as described above, in order for the sensor 3 to reliably detect the magnetism from the adjacent detection object and sufficiently suppress the detection of the magnetism from the distant magnetic generator, a current flows through the electric wire 402. Regardless of whether or not the sensor 3 outputs a difference signal Sm of a level corresponding to the magnetism M1 generated in the electric wire 401, it can be accurately inspected whether or not a current is flowing through the electric wire 401.

また、一対の磁気検出素子４１を備えてセンサ３を構成した例について上記したが、センサの構成はこれに限定されない。一例として、図７に示すセンサ５０３は、同じ磁気検出特性を有している磁気検出素子５４１ａ，５４１ｃ、および磁気検出素子５４１ａ，５４１ｃとは磁気検出特性の異なる磁気検出素子５４１ｂ（以下、磁気検出素子５４１ａ，５４１ｂ，５４１ｃを区別しないときには「磁気検出素子５４１」ともいう）の合計３つの磁気検出素子を備えて構成されている。この場合、一例として、磁気検出素子５４１ａ，５４１ｃの検出感度Ｓがそれぞれ２．５Ｖ／Ｏｅに規定され、磁気検出素子５４１ｂの検出感度Ｓが５．０Ｖ／Ｏｅに規定されている。なお、磁気検出素子５４１の検出感度Ｓはこれらの各値に限定されず、互いに極性を異ならせて合計したときの合計値が０となる任意の値に規定することができる。また、各磁気検出素子５４１は、所定の距離ｄ（一例として２．２ｍｍ程度）だけ互いに離間した状態でケース５４３の内部に直線的に配置（収容）されている。なお、必ずしも各磁気検出素子５４１を直線的に配置する必要はなく、磁気（磁束）の方向に応じて、磁気強度が等しい範囲内で各磁気検出素子５４１の位置を直線上からずらして配置してもよい。また、このセンサ５０３では、差動回路５３２が、各磁気検出素子５４１のうちの中央に位置する１つの磁気検出素子５４１（この例では、磁気検出素子５４１ｂ）によって出力される検出信号Ｓｄと、その磁気検出素子５４１を除く他の磁気検出素子５４１（この例では、磁気検出素子５４１ａ，５４１ｃ）によって出力される両検出信号Ｓｄを加算した信号との差分信号Ｓｍを出力する。具体的には、センサ５０３は、例えば、磁気検出素子５４１ｂの検出信号Ｓｄから、磁気検出素子５４１ａの検出信号Ｓｄと磁気検出素子５４１ｃの検出信号Ｓｄとを差し引いて差分信号Ｓｍを出力する。このセンサ５０３では、図５に示すように、単一の磁気検出素子４１やセンサ３と比較して、検出対象体までの距離の増加に対する検出感度比の低下率が大きくなっている。このため、このセンサ５０３においても、センサ３と同様にして、例えば、多層の回路基板１０１における導体パターン１０２と集積回路１１１の端子１１２との接続状態の良否検査に対する検査精度を十分に向上させることができる。   Moreover, although it described above about the example which comprised the pair of magnetic detection elements 41 and comprised the sensor 3, the structure of a sensor is not limited to this. As an example, a sensor 503 shown in FIG. 7 includes magnetic detection elements 541a and 541c having the same magnetic detection characteristics, and magnetic detection elements 541b (hereinafter referred to as magnetic detection elements) having different magnetic detection characteristics from the magnetic detection elements 541a and 541c. The elements 541a, 541b, and 541c are configured to include a total of three magnetic detection elements (also referred to as “magnetic detection element 541” when not distinguished from each other). In this case, as an example, the detection sensitivity S of the magnetic detection elements 541a and 541c is defined as 2.5 V / Oe, and the detection sensitivity S of the magnetic detection element 541b is defined as 5.0 V / Oe. The detection sensitivity S of the magnetic detection element 541 is not limited to these values, and can be defined as an arbitrary value where the total value becomes 0 when the polarities are different from each other. The magnetic detection elements 541 are linearly arranged (accommodated) inside the case 543 in a state of being separated from each other by a predetermined distance d (about 2.2 mm as an example). Note that the magnetic detection elements 541 are not necessarily arranged linearly, and the positions of the magnetic detection elements 541 are shifted from the straight line within a range where the magnetic strength is equal according to the direction of magnetism (magnetic flux). May be. In the sensor 503, the differential circuit 532 includes a detection signal Sd output by one magnetic detection element 541 (in this example, the magnetic detection element 541b) located at the center of the magnetic detection elements 541, and A difference signal Sm from a signal obtained by adding both detection signals Sd output by other magnetic detection elements 541 (in this example, magnetic detection elements 541a and 541c) excluding the magnetic detection element 541 is output. Specifically, for example, the sensor 503 subtracts the detection signal Sd of the magnetic detection element 541a and the detection signal Sd of the magnetic detection element 541c from the detection signal Sd of the magnetic detection element 541b, and outputs the difference signal Sm. In this sensor 503, as shown in FIG. 5, the rate of decrease in the detection sensitivity ratio with respect to an increase in the distance to the detection object is larger than in the single magnetic detection element 41 or the sensor 3. For this reason, in this sensor 503 as well, for example, the inspection accuracy for the quality inspection of the connection state between the conductor pattern 102 and the terminal 112 of the integrated circuit 111 in the multilayer circuit board 101 can be sufficiently improved in the same manner as the sensor 3. Can do.

さらに、４つ以上の磁気検出素子を備えたセンサを採用することもできる。この場合、差動回路に入力させる際の各磁気検出素子からの各検出信号Ｓｄの極性を正および負のいずれかに規定し、かつ、この極性の正負を付加した各磁気検出素子の各検出感度Ｓの合計値が０となるように各磁気検出素子の検出感度Ｓを規定することにより、上記したセンサ３やセンサ５０３と同様の効果を実現することができる。   Furthermore, a sensor provided with four or more magnetic detection elements may be employed. In this case, the polarity of each detection signal Sd from each magnetic detection element when input to the differential circuit is defined as either positive or negative, and each detection of each magnetic detection element added with the positive / negative polarity of this polarity By defining the detection sensitivity S of each magnetic detection element so that the total value of the sensitivity S becomes 0, the same effects as those of the sensor 3 and the sensor 503 described above can be realized.

また、ＭＲセンサで磁気検出素子４１を構成した例について上記したが、ＭＲセンサに代えて、ＳＱＵＩＤ（超伝導量子干渉デバイス）や、ホール素子を用いて磁気検出素子４１を構成することもできる。さらに、電子回路基板１００における導体パターン１０２と集積回路１１１の端子１１２との接続状態の良否を基板検査装置１を用いて検査する例について上記したが、多層回路基板における導体パターン１０２の断線や短絡を検査する際に基板検査装置１を用いることもでき、この場合においても、上記した導体パターン１０２と端子１１２との接続状態の良否検査と同様にして、検査精度を十分に向上させることができる。   Moreover, although the example which comprised the magnetic detection element 41 with MR sensor was mentioned above, it replaced with MR sensor and can also comprise the magnetic detection element 41 using SQUID (superconducting quantum interference device) or a Hall element. Furthermore, although the example in which the quality of the connection state between the conductor pattern 102 in the electronic circuit board 100 and the terminal 112 of the integrated circuit 111 is inspected using the board inspection apparatus 1 has been described above, the conductor pattern 102 in the multilayer circuit board is disconnected or short-circuited. The substrate inspection apparatus 1 can also be used when inspecting the substrate, and in this case as well, the inspection accuracy can be sufficiently improved in the same manner as the above-described quality inspection of the connection state between the conductor pattern 102 and the terminal 112. .

基板検査装置１の構成を示す構成図である。1 is a configuration diagram showing a configuration of a substrate inspection apparatus 1. FIG. 基板検査装置１を用いた電子回路基板１００の集積回路１１１ａに対する検査の状態を示す説明図である。It is explanatory drawing which shows the state of the test | inspection with respect to the integrated circuit 111a of the electronic circuit board 100 using the board | substrate inspection apparatus 1. FIG. 基板検査装置１を用いた電子回路基板１００の集積回路１１１ｂに対する検査の状態を示す説明図である。It is explanatory drawing which shows the state of the test | inspection with respect to the integrated circuit 111b of the electronic circuit board 100 using the board | substrate inspection apparatus 1. FIG. 基板検査装置１を用いた電子回路基板１００の集積回路１１１ｃに対する検査の状態を示す説明図である。It is explanatory drawing which shows the state of the test | inspection with respect to the integrated circuit 111c of the electronic circuit board 100 using the board | substrate inspection apparatus 1. FIG. センサ３，５０３および単一の磁気検出素子４１（従来のブリッジ検出回路）における磁気の検出感度比の特性を示す特性図である。It is a characteristic view which shows the characteristic of the detection sensitivity ratio of the magnetism in the sensors 3,503 and the single magnetic detection element 41 (conventional bridge detection circuit). 検査装置３００の使用方法を説明するための説明図である。It is explanatory drawing for demonstrating the usage method of the inspection apparatus. センサ５０３の構成を示す構成図である。2 is a configuration diagram showing a configuration of a sensor 503. 従来のブリッジ検出回路を用いた集積回路２１１ａに対する検査の状態を示す説明図である。It is explanatory drawing which shows the state of a test | inspection with respect to the integrated circuit 211a using the conventional bridge | bridging detection circuit. 従来のブリッジ検出回路を用いた集積回路２１１ｂに対する検査の状態を示す説明図である。It is explanatory drawing which shows the state of the test | inspection with respect to the integrated circuit 211b using the conventional bridge | bridging detection circuit. 従来のブリッジ検出回路を用いた集積回路２１１ｃに対する検査の状態を示す説明図である。It is explanatory drawing which shows the state of a test | inspection with respect to the integrated circuit 211c using the conventional bridge | bridging detection circuit.

符号の説明Explanation of symbols

１ 基板検査装置
３，５０３ センサ
５，３０５ 制御部
３２ 差動アンプ
４１ａ，４１ｂ，５４１ａ〜５４１ｃ 磁気検出素子
１０２，１０２ａ〜１０２ｈ，１０３ 導体パターン
１１２，１１２ａ〜１１２ｃ 端子
３００ 検査装置
５３２ 差動回路
ｄ 距離
Ｍ１，Ｍ２ 磁気
Ｓｄ，Ｓｄａ，Ｓｄｂ 検出信号
Ｓｍ 差分信号 1 Board inspection equipment
3,503 sensors
5,305 Control unit 32 Differential amplifier 41a, 41b, 541a to 541c Magnetic detection element 102, 102a to 102h, 103 Conductor pattern 112, 112a to 112c Terminal 300 Inspection device 532 Differential circuit
d Distance M1, M2 Magnetic Sd, Sda, Sdb Detection signal Sm Difference signal

Claims (4)

所定距離だけ互いに離間した状態で配置される一対の磁気検出素子と、前記各磁気検出素子によってそれぞれ出力される検出信号の差分信号を出力する差動回路とを備えているセンサ。   A sensor comprising a pair of magnetic detection elements arranged in a state of being separated from each other by a predetermined distance, and a differential circuit that outputs a differential signal of detection signals respectively output by the magnetic detection elements. 前記各磁気検出素子は、同一の磁気検出特性を有している請求項１記載のセンサ。   The sensor according to claim 1, wherein each of the magnetic detection elements has the same magnetic detection characteristic. 所定距離だけ互いに離間した状態で配置される３つの磁気検出素子と、前記各磁気検出素子のうちの中央に位置する１つの当該磁気検出素子によって出力される検出信号と他の前記磁気検出素子によって出力される検出信号との差分信号を出力する差動回路とを備えているセンサ。   By three magnetic detection elements arranged in a state of being separated from each other by a predetermined distance, a detection signal output by one magnetic detection element located in the center of the magnetic detection elements, and the other magnetic detection elements A sensor comprising: a differential circuit that outputs a differential signal with respect to an output detection signal. 請求項１から３のいずれかに記載のセンサと、当該センサによって出力される前記差分信号に基づいて磁気発生体についての電気的パラメータを検査する検査部とを備えている検査装置。   An inspection apparatus comprising: the sensor according to claim 1; and an inspection unit that inspects an electrical parameter of the magnetic generator based on the difference signal output by the sensor.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016114479A (en) * 2014-12-16 2016-06-23 日置電機株式会社 Data creation device and data creation method

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JPH04372879A (en) * 1991-06-21 1992-12-25 Sanyu Kogyo Kk Inspection of disconnection of hot wire in frosted glass for car
JP2004184303A (en) * 2002-12-05 2004-07-02 Seiko Instruments Inc Method and apparatus for inspecting electric wire provided with function of removing disturbance
WO2005036194A2 (en) * 2003-10-08 2005-04-21 Centre National D'etudes Spatiales Magnetic-field-measuring probe

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04372879A (en) * 1991-06-21 1992-12-25 Sanyu Kogyo Kk Inspection of disconnection of hot wire in frosted glass for car
JP2004184303A (en) * 2002-12-05 2004-07-02 Seiko Instruments Inc Method and apparatus for inspecting electric wire provided with function of removing disturbance
WO2005036194A2 (en) * 2003-10-08 2005-04-21 Centre National D'etudes Spatiales Magnetic-field-measuring probe

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016114479A (en) * 2014-12-16 2016-06-23 日置電機株式会社 Data creation device and data creation method

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